The original 2nd Edition entry from the Forge.

Diablo is a cruel and visciously designed two-handed sword. The sword is over 6' long and has a double-sided toothed blade. The hilt is made of red steel with a large triangular ruby at the center. The handle is carved from a Pit Fiend's rib bone. The sword was created by a Balor who thought it would be humorous to kill Baatezu with a sword made from one of their own. The plan backfired when the Pit Fiends spirit prevented the sword from being used against other Baatezu.

Diablo is a two-handed sword +3/ +6 vs. tanari. The blade has a EGO 20, INT 19 and has a lawful evil alignment. Despite its evil nature, the sword will gladly align itself with any non-chaotic warrior. He is especially fond of owners that fight Tanari. On the down side, if Diablo is brought to bear against a Baatezu, it becomes a two-handed sword -3. The sword can absorb lightning and electricity, including the effects of a Balor's lighting blade. It also acts as a ring of fire resistance. It will hum unerringly whenever a Tanari is within 100 feet.